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Invasive pathogens threaten amphibian diversity Annemarieke Spitzen ([email protected]) Wageningen, 24 June 2016 Introduction § It’s not easy bein’ green § Midst 6th mass extinction § > 40% all amphibians threatened § Chytridiomycosis more devastating than any infectious wildlife disease § > 200 amphibian species collapsing to or near extinction 2/20 Blaustein et al Ann. N.Y. Acad. Sci. 2011 Wake et al PNAS 2008 Stuart et al Science 2004 Skerratt et al EcoHealth 2007 Worrisome § Amphibians are key for ecosystem stability 3/20 § Caudates are considered so important to ecosystems that their presence has been used as a cost-effective indicator of ecological health and integrity Micacchion 2004 Best & Welsh Ecosphere 2014 Gray et al. PloSPathogens 2015 Davic &Welsh Ann. Rev. EES 2004 Worrisome § Ambystoma talpoideum; 902 mosquitoes/day § Osteopilus septentrionalis; 13 – 21 Culex larvae/day § Decrease in algae by herbaceous tadpoles § Euryphagic § Terrestrial salamanders may impact on decomposition rate and soil dynamics (underground burrows) M. Hollander 4/20 James H. Harding Durant & Hopkins Can J Zool 2008 Rodríguez & Gonzáles B Malariología 2000 Wyman Biodiv.& Cons 1998 Walton & Steckler Pedobiol 2005 Hocking & Babbit Herp Cons Biol 2014 Worrisome § Provisioning services • Food, medicine and bait § Cultural services • Art, jewellery, theatre Macbeth 1605 § Regulating services Salamandra (Jacob van Maerlant, 1270) Mark Dion, 2015 Brandon Ballengée, 2014 5/20 Picco & Collins Cons Biol 2008 Hocking & Babbit Herp Cons Biol 2014 EID § Of course diseases are natural phenomenon, structure ecological communities § However some diseases are more equal than others § Ranavirosis and Chytridiomycosis 6/20 Chytridiomycosis § The IUCN has called amphibian chytridiomycosis “the worst infectious disease ever recorded among vertebrates in terms of the number of species impacted, and its propensity to drive them to extinction.” 7/20 Chytridiomycosis § Both cause an erosive skin disease and rapid mortality § Both infect a broad amphibian host range § They may cause the total collapse of amphibian populations § Their spread is enhanced by global trade and traffic 8/20 Martel et al PNAS 2013 Martel et al Science 2014 Chytridiomycosis § They occupy different ecological niches e.g. - different optimal growth temperatures Bd: 17-25˚C - 9/20 Bsal: 10-15˚C Bsal is restricted to urodelan hosts Martel et al PNAS 2013 Martel et al Science 2014 B. salamandrivorans § Disease symptoms § Life cycle § Origin F. Pasmans Pathology consistently comprises of multifocal superficial erosions and deep ulcerations in the skin 10/20 Life cycle Bsal 5 days at 15˚C 2 life stages: motile zoospore and thallus (reproductive body) © Sergé Bogaerts Martel et al PNAS 2013 Martel et al Science 2014 Van Rooij et al Vet Res 2015 Worrisome § At the brink of losing entire group by infectious disease § And we don’t know what that means for ecosystem stability 11/20 Bosch Div & Distr 2008 Effect of Bsal § Much remains to be discovered § For example on the 12/20 • Pathways and modes of spread • Natural variation in host susceptibility • Possibility of increasing host resistance • Role of biotic and abiotic parameters • Role of species composition and reservoir hosts • Human involvement • ….. • …… Martel et al PNAS 2013 Pathways and mode of spread § Patchy Bsal distribution § Bd can spread quickly (25 – 282 km/yr) § Bsal less aquatic than Bd § Bsal does not infect caudate larvae ravon.nl/Bsal 13/20 Spitzen-van der Sluijs et al EID 2016 Lips et al PloS Biol 2008 Martel et al Science 2014 Van Rooij et al Vet Res 2015 Pathways and mode of spread § Patchy Bsal distribution § Bd can spread quickly (25 – 282 km/yr) § Bsal less aquatic than Bd § Bsal does not infect caudate larvae § May hitch with birds and boots • But..very poorly resists dessication and heat § (Pet) trade 14/20 Spitzen-van der Sluijs et al EID 2016 Lips et al PloS Biol 2008 Martel et al Science 2014 Van Rooij et al Vet Res 2015 Cunningham et al Vet Rec 2015 Sabino-Pinto et al AR 2015 Picco & Collins Cons Biol 2008 Tolerance? § 99.9% decrease of natural fire salamander population (’97 – ’14) § Similar reports from Germany § Species differences? 15/20 Tolerance? § Common midwife toad (Alytes obstetricans) 16/20 Bosch et al 2001 Spitzen – van der Sluijs et al. Cons Biol 2014 Biotic and abiotic parameters § Strong context dependency • Skin bacteria and peptides - Inoculation of Janthinobacterium lividum • Treatment in captivity © Sergé Bogaerts 17/20 Pasmans et al PloS ONE 2013 Blooi et al Sci Rep 2015a Blooi et al Sci Rep 2015b Ackleh et al 2016 Biotic and abiotic parameters § Species composition § Landscape level § Pollution (e.g. biocides) § Co-infection multiple pathogens § Climate change and effect on ambient (focal) temperature 18/20 Future work § Focus on mitigation at level of salamander/newt and fungus § Modes of spread (actual action possible) § Possibilities of conservation endemic European species S. atra aurorae S. lanzai Calotriton arnoldi S. atra pasubiensis 19/20 Photos: © Sergé Bogaerts Take home message [email protected] [email protected] 20/20 [email protected]
